constants

问题 I'm doing a practical assignment for university and I've run into a problem. I've got a class that declares this method: bool graficarTablero(const Tablero *&tablero, const string &nombreArchivo); I want to pass a pointer to an object Tablero by constant reference. If I call that function like, say for example: ArchivoGrafico *grafico = new ArchivoGrafico; if(grafico->graficarTablero(tablero, ARCHIVO_GRAFICO)){ ... ...I get compilation errors. Ok, I won't detail the error I get cause I think

问题 I'm doing a practical assignment for university and I've run into a problem. I've got a class that declares this method: bool graficarTablero(const Tablero *&tablero, const string &nombreArchivo); I want to pass a pointer to an object Tablero by constant reference. If I call that function like, say for example: ArchivoGrafico *grafico = new ArchivoGrafico; if(grafico->graficarTablero(tablero, ARCHIVO_GRAFICO)){ ... ...I get compilation errors. Ok, I won't detail the error I get cause I think

问题 As the title states, I would really like to clarify this. I have read a few articles and postings here on this topic, something just isn't clicking for me. I'll add I'm a bit new to Php. OK, here's what I want to understand; namespace Information; define('ROOT_URL', 'information/'); define('OFFERS_URL', ROOT_URL . 'offers/'); namespace Products; define('ROOT_URL', 'products/'); define('OFFERS_URL', ROOT_URL . 'offers/'); I want the constants to be constructable, ie, build constants from base

问题 As the title states, I would really like to clarify this. I have read a few articles and postings here on this topic, something just isn't clicking for me. I'll add I'm a bit new to Php. OK, here's what I want to understand; namespace Information; define('ROOT_URL', 'information/'); define('OFFERS_URL', ROOT_URL . 'offers/'); namespace Products; define('ROOT_URL', 'products/'); define('OFFERS_URL', ROOT_URL . 'offers/'); I want the constants to be constructable, ie, build constants from base

问题 I understand one of the big deals about constants is that you don't have to go through and update code where that constant is used all over the place. Thats great, but let's say you don't explicitly declare it as a constant. What benefit(s) exist(s) to take a variable that HAPPENS to actually not be changed and make it a constant, will this save on processing, and/or size of code...etc? Basically I have a program that the compiler is saying that a particular variable is not changed and thus

问题 I'm coming back to some C development after working in C++ for a while. I've gotten it into my head that macros should be avoided when not necessary in favor of making the compiler do more work for you at compile-time. So, for constant values, in C++ I would use static const variables, or C++11 enum classes for the nice scoping. In C, static constants are not really compile-time constants, and enums may (? or may not?) behave slightly differently. So, is it reasonable to prefer using enums

问题 Simple question - why does the Decimal type define these constants? Why bother? I'm looking for a reason why this is defined by the language, not possible uses or effects on the compiler. Why put this in there in the first place? The compiler can just as easily in-line 0m as it could Decimal.Zero, so I'm not buying it as a compiler shortcut. 回答1: Small clarification. They are actually static readonly values and not constants. That has a distinct difference in .Net because constant values are

问题 Why does C# not allow const and static on the same line? In Java, you must declare a field as 'static' and 'final' to act as a constant. Why does C# not let you declare const's as final? I make the further distinction that in Java, every interface is public and abstract, whether this is explicitly declared or not. Aren't const's effectively static in nature? WHy does C# balk at this? 回答1: const and static really do mean different things, different storage mechanism, different initialisation.

问题 How is it recommended to create constants in Kotlin? And what's the naming convention? I've not found that in the documentation. companion object { //1 val MY_CONST = "something" //2 const val MY_CONST = "something" //3 val myConst = "something" } Or ...? 回答1: In Kotlin, if you want to create the local constants which are supposed to be used with in the class then you can create it like below val MY_CONSTANT = "Constants" And if you want to create a public constant in kotlin like public

问题 I have the following code from Codeigniter index.php My understanding is that, If / of string position in $system_folder (in this case CIcore_1_7_1) is false , and if realpath function exists AND (?) is not false , $system_folder is assigned to (?) /$system_folder . else $system_folder is assigned to $system_folder with replacing \\ with / . Q1. What does realpath function means? Q2. What does this mean? @realpath(dirname(__FILE__)) Q3. Am I right? Do I have any misunderstanding? Q4. What